}

#if OPENSSL_VERSION_NUMBER < 0x10100000L
    OpenSSL_add_all_algorithms(); /* Load ciphers and digests */
#endif

    SSL_CTX_set_app_data(ctx, (void*)interp);	/* remember the interpreter */
    SSL_CTX_set_options(ctx, SSL_OP_ALL);	/* all SSL bug workarounds */
    SSL_CTX_set_options(ctx, SSL_OP_NO_COMPRESSION);	/* disable compression even if supported */
    SSL_CTX_set_options(ctx, off);		/* disable protocol versions */
#if OPENSSL_VERSION_NUMBER < 0x10101000L
    SSL_CTX_set_mode(ctx, SSL_MODE_AUTO_RETRY);	/* handle new handshakes in background. On by default in OpenSSL 1.1.1. */
#endif
    SSL_CTX_set_options(ctx, SSL_OP_ALL);	/* Enable all SSL bug workarounds */
    SSL_CTX_set_options(ctx, SSL_OP_NO_COMPRESSION);	/* Disable compression even if supported */
    SSL_CTX_set_options(ctx, off);		/* Disable specified protocol versions */

    /* Allow writes to report success when less than all records have been written */
    SSL_CTX_set_mode(ctx, SSL_MODE_ENABLE_PARTIAL_WRITE);

    /* Disable attempts to try to process the next record instead of returning after a
       non-app record. Avoids hangs in blocking mode, when using SSL_read() and a
       non-application record was sent and no application data was sent. */
    SSL_CTX_clear_mode(ctx, SSL_MODE_AUTO_RETRY);

    SSL_CTX_sess_set_cache_size(ctx, 128);

    /* Set user defined ciphers, cipher suites, and security level */
    if ((ciphers != NULL) && !SSL_CTX_set_cipher_list(ctx, ciphers)) {
	Tcl_AppendResult(interp, "Set ciphers failed: No valid ciphers", (char *) NULL);
	SSL_CTX_free(ctx);
	return NULL;